In-Line Schlieren System

The in-line type of schlieren system shares the same working principle as the one featuring Z-shaped light path. However, instead of using mirrors, the in-line system makes use of lenses. There are pros and cons of this type of schlieren systems:

Pros:

Samller space needed due to shorter focal length;

Highly integrated design, light source and aperature are integrated into the lens tube, as well as the knife-edge.

Easy to setup, every component is aligned along the straight line.

Cons:

The lens is a doublet, higher manufacturing cost.